1. Field of the Invention
The present invention relates to an audio signal processing apparatus and an audio signal processing system.
2. Description of the Related Art
Conventionally, an imaging apparatus has been equipped with a function of processing an audio signal obtained with a built-in microphone, an external microphone, or the like, and recording and sending to the outside the audio signal. The imaging apparatus can individually record audio data on a recording medium, record audio data together with moving image data, or record audio data after associating the audio data with still image data. In such an imaging apparatus, noise may be generated as a zoom lens or a focus lens in the imaging apparatus moves or a diaphragm in the imaging apparatus is opened and closed (a drive unit is driven). More specifically, noise may be generated by the driving of the imaging apparatus, and a sound may become difficult to hear when the acquired audio signal is reproduced.
For such an issue, Japanese Patent Application Laid-Open No. 2008-053802, for example, discusses a technique for reducing a noise component included in an audio signal in a section where noise is generated by movement of a magnetic head caused by intermittent recording of a hard disk. Therefore, in Japanese Patent Application Laid-Open No. 2008-053802, a “predicted audio signal” is generated based on audio signals obtained before and after a section where noise is generated (a noise generation section), and is recorded in place of a sound in the noise generation section.
In Japanese Patent Application Laid-Open No. 2008-053802, however, the hard disk is intermittently driven at predetermined intervals, so that the noise caused by the movement of the magnetic head is generated once every several seconds. Therefore, the noise caused by the movement of the magnetic head is not mixed into the audio signals obtained before and after the noise generation section, which are used to generate the predicted audio signal, to be substituted for the sound in the noise generation section. When the hard disk is driven at short time intervals, or when another drive unit is driven, for example, however, noise is mixed into the audio signals obtained before and after the noise generation section, and the noise also affects the “predicted audio signal” generated based on those audio signals. When the hard disk is driven immediately after the recording is started, or when the recording is stopped immediately after the hard disk is driven, there are no audio signals obtained before and after the noise generation section, so that the “predicted audio signal” is not satisfactorily generated.